When scientist Michael Kozlov was forced to help an unnamed Communist country build and test nuclear bombs, he purposely picked an area that legend said a mighty dragon was buried. His theory was right, and the explosions released Grogg, who then destroyed the military overseeing the tests.

Kozlov managed to escape, and at last notice, Grogg was left unchecked in his native land, free to roam.

Dr. Kozlov also revealed that Grogg was but one of a large number of dragons that once roamed Eurasia, and that the Great Wall of China was originally built as a blockade to keep them contained. What happened to the rest of these dragons is a mystery, but given Grogg's resemblance to Fin Fang Foom, there's a possibility the two are of the same race, especially given the revelation that Foom himself was part of a large invasion of dragon-like creatures.

In an alternate reality, Grogg was one of several aliens and monsters summoned by the villain Jack O' Lantern to attack the world. The creatures were defeated by a group of supernatural crusaders.